How does the USPTO determine if a subcombination has separate utility?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

The USPTO determines if a subcombination has separate utility by assessing whether it can be used independently of the combination. According to MPEP 806.05(a):

“To support a requirement for restriction between combination and subcombination inventions, both two-way distinctness and reasons for insisting on restriction are necessary, i.e., there would be a serious search burden if restriction were not required as evidenced by separate classification, status, or field of search.”

The examiner must show that:

• The subcombination has utility other than in the disclosed combination.
• The combination does not require the particulars of the subcombination as claimed for patentability.

For example, a nail (subcombination) has separate utility from a hammer (combination) as it can be used with other tools or by hand.